Basic animal research demonstrates that controllability over drug intake can powerfully moderate responses to drug administration. Unfortunately, there is limited experimental research in humans that examines how controllability over intake moderates drug responses. This research is particularly relevant for human drug abuse such as tobacco use, which represents the most preventable cause of death in this nation. An understanding of how behavioral contingencies moderate drug responses -may lead to the development of more effective treatment adjuncts (e.g., use of scheduled smoking as a smoking cessation treatment). Fortunately, a methodology has been developed that allows for the manipulation of controllability while equating for dosing, consumption pattern, and exposure to other stimuli. Such a procedure is often referred to as a yoked-box, or triadic, design and has been utilized extensively in basic animal research examining the effects of controllable versus uncontrollable exposure to various stimuli. The goal of this project is to develop and test the feasibility of a human lab-based yoking procedure that utilizes smoking puff topography information. Utilizing a new methodology, this project will replicate and extend the findings of previous lab-based human research. For this preliminary study, a single group of human participants will be examined under conditions of controllable smoking versus uncontrollable smoking. During the first test session, each participant will smoke contingently (i.e. have control over intake). During the second test session, each participant will smoke noncontingently according to the pattern of intake previously recorded during the contingent smoking session (i.e., each subject yoked to his/her own previously determined pattern). Delivery of each puff will be regulated by a smoking topography system. Such a procedure ensures that characteristics related to drug intake (e.g., dose, pattern) are equated between contingent- versus noncontingent-conditions. Measures collected will include subjective, cardiovascular, and behavioral responses to smoking. This study will extend previous work by examining the reward/incentive value of regular ad-lib smoking immediately following exposure to these experimental conditions (e.g., work to obtain ad-lib cigarettes, latency to first cigarette during subsequent ad-lib smoking). By extending previous findings and increasing knowledge about the utility of this approach, results from this project will directly inform the design of future research examining how behavioral factors moderate responses to drug intake, influence drug-seeking behavior, and ultimately can be utilized in designing effective interventions for addiction.